Flatten a PDF
What is written stays written — nothing can be changed any more.
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How to flatten a PDF, step by step
Flattening a PDF merges its form fields and annotations into the page content, in a single action, with nothing to configure.
Drop in the PDF to flatten
The page count and the number of detected form fields appear right away.
Note the warning if no field is found
VellumPDF states it plainly — the effect will be limited, but nothing stops you from continuing.
Click “Flatten the document”
There is no checkbox and no option to pick: VellumPDF merges the form fields and annotations into every page’s content in one go.
Download the flattened file
The resulting document now looks identical everywhere, and its fields can no longer be edited.
If the PDF has no form fields, VellumPDF flattens it anyway without error: the produced file is then simply identical to the one dropped in. Flattening does not remove text hidden under an annotation — to remove content, use the redaction tool.
Frequently asked questions
What does flattening a PDF with form fields do?
It merges filled-in fields and annotations into the page content, producing a frozen document where nothing can be changed, unticked or moved by mistake — useful before archiving a completed form.
Is flattening reversible?
No, once fields and annotations are merged into the content, they can no longer be edited or reactivated as interactive fields. Keep the original if you think you’ll still need to edit the form.
Does this tool send the document to a server?
No, the operation runs entirely in your browser, and the tool is free. A password-protected PDF must first be unlocked before it can be flattened.
Is flattening the same as protecting a PDF?
No. Flattening freezes the appearance: fields can no longer be filled in and annotations no longer move. It prevents neither copying the text, nor printing, nor later editing with an editor. To restrict what can be done with the file, protect it; to actually remove a piece of information, redact it.
Does flattening remove the text hidden under an annotation?
No, and this is the costliest misunderstanding. A black rectangle drawn over a passage is still a drawing: after flattening it becomes part of the page content, but the text underneath is still in the file and can be copied. To make information disappear, use the redaction tool, which removes the text from the file it produces.
What happens if the PDF contains no form fields at all?
The tool warns you: with no fields and no annotations there is nothing to merge into the page, and the document comes out practically unchanged. Flattening is only worth it on a completed form or an annotated document.